using UnityEditor;
using UnityEngine;
using UnityEngine.Localization;
using UnityEngine.Localization.Tables;
using UnityEditor.Localization;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

public class LocalizationMultiTableImporter
{
    [MenuItem("Localization/Import All Tables from CSV")]
    public static void ImportAllLocalizationTables()
    {
        string path = EditorUtility.OpenFilePanel("Import Localization CSV", "", "csv");
        if (string.IsNullOrEmpty(path)) return;

        string rawCsv = File.ReadAllText(path, Encoding.UTF8);
        var lines = SplitCSVRows(rawCsv);
        if (lines.Count < 2)
        {
            Debug.LogError("CSV file is empty or missing header.");
            return;
        }

        // Header: Table,Key,locale1,locale2,...
        var header = SplitCSVLine(lines[0]);
        if (header.Count < 3)
        {
            Debug.LogError("CSV header must contain at least 'Table,Key,<Locale>'");
            return;
        }

        var localeCodes = header.Skip(2).ToList();

        var locales = LocalizationEditorSettings.GetLocales();
        var localeMap = locales.ToDictionary(l => l.Identifier.Code, l => l);

        var collections = LocalizationEditorSettings.GetStringTableCollections();

        for (int lineIndex = 1; lineIndex < lines.Count; lineIndex++)
        {
            var line = lines[lineIndex];
            var cells = SplitCSVLine(line);
            if (cells.Count < 2) continue;

            string tableName = cells[0];
            string key = cells[1];

            var collection = collections.FirstOrDefault(c => c.TableCollectionName == tableName);
            if (collection == null)
            {
                Debug.LogWarning($"Skipping unknown table: {tableName}");
                continue;
            }

            for (int i = 0; i < localeCodes.Count; i++)
            {
                string localeCode = localeCodes[i];
                if (!localeMap.TryGetValue(localeCode, out var locale)) continue;

                var table = collection.GetTable(locale.Identifier) as StringTable;
                if (table == null)
                {
                    table = collection.AddNewTable(locale.Identifier) as StringTable;
                }

                var sharedData = collection.SharedData;
                var sharedEntry = sharedData.GetEntry(key);
                if (sharedEntry == null)
                {
                    sharedEntry = sharedData.AddKey(key);
                }

                var entry = table.GetEntry(sharedEntry.Id);
                if (entry == null)
                {
                    entry = table.AddEntry(sharedEntry.Id, "");
                }

                if (i + 2 < cells.Count)
                {
                    entry.Value = cells[i + 2];
                }

                EditorUtility.SetDirty(table);
            }
        }

        AssetDatabase.SaveAssets();
        Debug.Log(" Localization import complete!");
    }

    /// <summary>
    /// Splits CSV into rows, handling multiline quoted entries.
    /// </summary>
    private static List<string> SplitCSVRows(string csvText)
    {
        var rows = new List<string>();
        var sb = new StringBuilder();
        bool inQuotes = false;

        for (int i = 0; i < csvText.Length; i++)
        {
            char c = csvText[i];
            sb.Append(c);

            if (c == '"')
            {
                // Check for escaped quote
                if (i + 1 < csvText.Length && csvText[i + 1] == '"')
                {
                    sb.Append('"');
                    i++;
                }
                else
                {
                    inQuotes = !inQuotes;
                }
            }
            else if ((c == '\n' || c == '\r') && !inQuotes)
            {
                // Handle Windows \r\n
                if (c == '\r' && i + 1 < csvText.Length && csvText[i + 1] == '\n')
                {
                    sb.Append('\n');
                    i++;
                }

                rows.Add(sb.ToString().TrimEnd('\r', '\n'));
                sb.Clear();
            }
        }

        if (sb.Length > 0)
            rows.Add(sb.ToString().TrimEnd('\r', '\n'));

        return rows;
    }

    /// <summary>
    /// Splits a CSV line into fields, handling commas and quotes correctly.
    /// </summary>
    private static List<string> SplitCSVLine(string line)
    {
        var result = new List<string>();
        var sb = new StringBuilder();
        bool inQuotes = false;

        for (int i = 0; i < line.Length; i++)
        {
            char c = line[i];

            if (inQuotes)
            {
                if (c == '"')
                {
                    if (i + 1 < line.Length && line[i + 1] == '"')
                    {
                        sb.Append('"'); // escaped quote
                        i++;
                    }
                    else
                    {
                        inQuotes = false;
                    }
                }
                else
                {
                    sb.Append(c);
                }
            }
            else
            {
                if (c == '"')
                {
                    inQuotes = true;
                }
                else if (c == ',')
                {
                    result.Add(sb.ToString());
                    sb.Clear();
                }
                else
                {
                    sb.Append(c);
                }
            }
        }

        result.Add(sb.ToString());
        return result;
    }
}